Currently widely-used non-reused packaging articles like fast food dinner-pail, the cushioning materials for various precision instruments, etc. are all made from plastics, such as foamed polystyrene, foamed polyvinyl chloride, foamed polyurethane foamed polyethylene, polyethylene and polypropylene, etc. As these articles are all non-reused and can remain in the nature rather stably without being decomposed, the enormous littering has been causing serious pollution to the nature. In addition, our living environment is further worsened as freon which can destroy ozone layer is used in the production of these articles, especially in the process of foaming.
Paper has also been used to produce packaging articles like tablewares, but it is reported that paper-based articles cause even more serious pollution to the nature than the plastic ones, and the overall resource consumed in making paper-based articles is much more than plastic articles, for example, the amount of the steam used to make a paper cup is 12 times that of a foamed polystyrene cup, electricity is 36 times, the cooling water is twice and the consumption of oil product materials is almost the same (see "The Situations and Outlook of Packaging Industry", "China Package" Magazine, Vol. 13, No. 3, P. 14, 1993).
The non-reused tablewares produced by pressing starch, corn and paint straw with binder are also disclosed. But such articles have a dense structure and a heavier weight, thus require large quantity of raw materials, besides, it is difficult to be shaped in mould, and need a long time to bake, therefore, not suitable for large scale production.
Accordingly, it is desired to have such a novel material which possesses me foamed plastics-like properties, in the meantime can avoid the foamed plastics disadvantage-polluting the environment because of not being decomposed, thus the material can be easily processed with low energy-consumption like the famed plastics and suits for industrial mass production, while it is totally harmless to environment from it's manufacturing, use till discard.
The present applicant's application CN 1080301A disclosed a nonpolluting foamed material obtained by a process comprising thoroughly blending a plant fiber material, a conventional poisonless and harmless gelling material and water, foaming and ripening after adding an appropriate amount of foaming agent and foaming aids, wherein the plant fiber material comprises mainly fiberous material of 1-3 mm long. Because the fiber used is relatively short, the mechanical strength of the material derived from the mixture of the fiber and pure starch as gelling material is very low, and can not be processed into articles. The gelling material with better gelling property such as polyvinyl alcohol, alginate etc. has to be added in order to improve the mechanical strength. Since these gelling materials are rather expensive, the cost of the articles made form them is increased.